Source: https://guthlabs.ai/docs/instruments/creatinine-clearance-cockcroft-gault/

instrument / verified-clean

# Creatinine Clearance (Cockcroft-Gault)

The current ledger marks this instrument verified clean within the source-bound verification corpus.

Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**

## Inspectable records

[01**Overview**Purpose and lifecycle](<https://guthlabs.ai/docs/instruments/creatinine-clearance-cockcroft-gault/>)[02**Mechanism**Method and assumptions](<https://guthlabs.ai/docs/instruments/creatinine-clearance-cockcroft-gault/mechanism/>)[03**Implementation**Binding and validation](<https://guthlabs.ai/docs/instruments/creatinine-clearance-cockcroft-gault/implementation/>)[04**Qualification**Evidence and errata](<https://guthlabs.ai/docs/instruments/creatinine-clearance-cockcroft-gault/qualification/>)

## Ledger state

The current ledger marks this instrument verified clean within the source-bound verification corpus.

**Area**: Biology, Medicine & Pharmacology (educational estimates only — every panel labeled not-medical-advice)

**Tranche**: tranche-4

**Evidence ID**: t4-002

**Ledger rows**: 1

No ledger note is attached.

## Review findings

NEEDS_REVIEW because the exact weight convention and the allowed/meaningful sex categories are ambiguous. The educational, not-medical-advice label is appropriate, but the interface should also explicitly distinguish estimated Cockcroft-Gault creatinine clearance from eGFR and enforce positive SCr, positive weight, and valid age constraints.

### Formula and scope findings

- The algebraic formula is the standard Cockcroft-Gault form when age is in years, weight is in kg, and serum creatinine is in mg/dL.

- The weight definition is unspecified: actual body weight, ideal body weight, or adjusted body weight may be selected clinically depending on body composition and institutional dosing policy.

- The sex adjustment is represented only as a binary 0.85 multiplier; the applicable sex category and handling of patients who do not fit that binary input are unspecified.

- The formula does not state an applicable age range or constraints for physiologically valid inputs.

### Unit assumptions

- Age is measured in completed years.

- Weight is measured in kilograms.

- Serum creatinine (SCr) is measured in mg/dL; a value reported in µmol/L must be divided by 88.4 before use.

- The resulting CrCl is reported in mL/min without automatic normalization to body-surface area.

- The 0.85 multiplier is applied for female input and 1.00 otherwise, subject to the sex-category ambiguity noted above.

## Boundary hardening

**BREAK_CLAIMED** · SELF_FLAGGED

A serum creatinine input of exactly zero produces division by zero, so the instrument must reject the input or return an explicit undefined result rather than a numeric clearance.

## Errata and corrections

No applied erratum is attached to this unique-name record.

## Inspectable example

4 review vectors are recorded. One source-bound sample is shown below.

````
{
  "inputs": {
    "age_years": 50,
    "weight_kg": 70,
    "sex": "male",
    "serum_creatinine_mg_dL": 1
  },
  "expected_outputs": {
    "creatinine_clearance_mL_min": 87.5
  },
  "working": "140 − 50 = 90; 90 × 70 = 6300; female factor = 1.00; denominator = 72 × 1.0 = 72; CrCl = 6300 ÷ 72 = 87.5 mL/min."
}
````

## Related workflows

[Renal Dosing Chain (education)CrCl](<https://guthlabs.ai/docs/instrument-workflows/renal-dosing/>)

## Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`

- `evidence-tranche4/tranche4-results.json`

- `BOUNDARY_HAZARD_CATALOG.json`